Hey there, working on a 500 gallon offset, and the doors opened up a bit too much. The way I've corrected them before is by putting 2x4 pine or 2x2 square tubing underneath the door horizontally and using ratchet straps to pull them in. I was nervous that the section in between the doors on the tank/CC side might flatten out some where the board/brace is placed from the pressure of the straps. Wanted to know of any tricks you guys might have...?? Thanks again as always.

Always easier to cut door completely off. Much easier to work with and weld flange on with it off. much less chance of it binding as well since you can account for the thickness of it when putting on the hinges.

I would caution on ratchet straps. Most are only rated in the 1000-2000 range. A heavy chain and bottle jack will work much easier.

Just to clarify....cut door completely out. Weld flanges all the way on. And then stretch with chain or something similar? Would you still do same process with a 1000 gallon that is nearly 3/8" thick? Thanks again

Yes on the method, you can weld the flange after you shape the door. My lid was 3/8'' X 42' long and it was pretty tough to bend but I got it really close to the original shape. It was also very heavy so I made a cardboard template of the radius of the tank so that I didn't have to keep lifting the door to check the fit. I believe that I would build cabinet doors on a 1000 gallon tank if the door warped but that's just my opinion.

With that method, I had thought it wasn't good to remove doors from tank....I thought the process was to weld hinges on before cutting the final cuts on door??

I made my Door with removable hinges cause you never know. I always like the option to do maintenance later and try to think ahead on stuff I weld up permanent, but thats just me.

Nothing wrong with your design and thinking ahead is always a good thing to do. My thought is as long as I have a grinder and a welder it is easier to weld things together rather than fabricate extra parts. If needed (in your hinge example) I can always cut the hinges off and weld new ones one.

It took me a while to get to this point. I was used to bolts and had a hard time committing to permanent welds.